Cognitive dysfunction in early experimental metabolic dysfunction-associated steatotic liver disease is associated with systemic inflammation and neuroinflammation.

Background & Aims: Cognitive dysfunction is an increasingly recognised manifestation of metabolic dysfunction-associated steatotic liver disease (MASLD), but the mechanistic link remains unclear. The aim of this study was to investigate the hypothesis that experimental MASLD leads to cognitive dysfunction via systemic inflammation and neuroinflammation. Methods: Twenty male Sprague Dawley rats were randomised to a high-fat high-cholesterol (HFHC) diet to induce MASLD, or a standard diet (n = 10/group), for 16 weeks. Assessments included: MASLD severity (histology), neurobehaviour, inflammation (liver, plasma and cerebrospinal fluid), brain microglia and astrocyte activation, and synaptic density. Results: The HFHC diet induced MASLD with extensive steatosis and lobular inflammation without fibrosis. Several plasma cytokines were elevated (CXCL1, IL-6, IL-17, MIP-1α, MCP-1, IL-10; all p <0.05) and correlated with increases in hepatic chemokine gene expression. Cerebrospinal fluid concentrations of CXCL1 were elevated (p = 0.04). In the prefrontal brain cortex, we observed a 19% increase in microglial activation confirmed by Iba1 immunohistochemistry (p = 0.03) and 3H-PK11195 autoradiography (p <0.01). In parallel, synaptic density was reduced to 92%, assessed by 3H-UCB-J autoradiography (p <0.01). MASLD animals exhibited impaired memory to previously encountered objects in the novel object recognition test (p = 0.047) and showed depression-like behaviour evidenced by increased immobility time (p <0.01) and reduced swimming time (p = 0.03) in the forced swim test. Conclusions: Experimental non-fibrotic MASLD, as a model to reflect the early stage of human disease, results in cognitive impairment and depression-like behaviour. This is associated with an inflammatory phenotype not only in the liver but also in the plasma and brain, which together with diminished synaptic density, provides a pathophysiological link between liver disease and cognitive dysfunction in MASLD. Impact and implications: Cognitive dysfunction is an increasingly recognised comorbidity in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), yet the underlying mechanisms remain unclear. This study provides evidence of impaired memory and depression-like symptoms in early experimental MASLD and indicates that hepatic inflammation may drive a systemic inflammatory response, resulting in neuroinflammation and reduced brain synaptic density. The evidence of impaired memory in MASLD and establishing its underlying pathophysiological link provides insights that could guide the development of potential new treatments for this increasingly common condition in people of working age. The study also emphasises the need to develop better tools for clinical cognitive testing, which will enable physicians to assess and manage brain dysfunction early in MASLD.

Role of ammonia in NAFLD: An unusual suspect.

Mechanistically, the symptomatology and disease progression of non-alcoholic fatty liver disease (NAFLD) remain poorly understood, which makes therapeutic progress difficult. In this review, we focus on the potential importance of decreased urea cycle activity as a pathogenic mechanism. Urea synthesis is an exclusive hepatic function and is the body's only on-demand and definitive pathway to remove toxic ammonia. The compromised urea cycle activity in NAFLD is likely caused by epigenetic damage to urea cycle enzyme genes and increased hepatocyte senescence. When the urea cycle is dysfunctional, ammonia accumulates in liver tissue and blood, as has been demonstrated in both animal models and patients with NAFLD. The problem may be augmented by parallel changes in the glutamine/glutamate system. In the liver, the accumulation of ammonia leads to inflammation, stellate cell activation and fibrogenesis, which is partially reversible. This may be an important mechanism for the transition of bland steatosis to steatohepatitis and further to cirrhosis and hepatocellular carcinoma. Systemic hyperammonaemia has widespread negative effects on other organs. Best known are the cerebral consequences that manifest as cognitive disturbances, which are prevalent in patients with NAFLD. Furthermore, high ammonia levels induce a negative muscle protein balance leading to sarcopenia, compromised immune function and increased risk of liver cancer. There is currently no rational way to reverse reduced urea cycle activity but there are promising animal and human reports of ammonia-lowering strategies correcting several of the mentioned untoward aspects of NAFLD. In conclusion, the ability of ammonia-lowering strategies to control the symptoms and prevent the progression of NAFLD should be explored in clinical trials.

Clearance and production of ammonia quantified in humans by constant ammonia infusion - the effects of cirrhosis and ammonia-targeting treatments.

BACKGROUND & AIMS: Hyperammonaemia is a key pathological feature of liver disease and the primary driver of hepatic encephalopathy (HE). However, the relative roles of increased ammonia production and reduced clearance are poorly understood as is the action of ammonia-targeting drugs for HE. We aimed to quantify whole-body ammonia metabolism in healthy persons and patients with cirrhosis and to validate our method by examining the effects of glycerol phenylbutyrate and lactulose + rifaximin treatment. METHODS: Ten healthy men and ten male patients with cirrhosis were investigated by 90-minute constant ammonia infusion to achieve steady-state plasma ammonia. Whole-body ammonia clearance was calculated as infusion rate divided by steady-state concentration increase and ammonia production was calculated as clearance multiplied by baseline ammonia concentration. Participants were re-investigated after the ammonia-targeting interventions. RESULTS: In healthy persons, ammonia clearance was 3.5 (3.1-3.9) L/min and ammonia production was 49 (35-63) µmol/min. Phenylbutyrate increased clearance by 11% (4-19%, p = 0.009). In patients with cirrhosis, ammonia clearance was 20% lower at 2.7 (2.1-3.3) L/min (p = 0.02) and production was nearly threefold higher at 131 (102-159) µmol/min (p <0.0001). Lactulose + rifaximin reduced production by 20% (2-37%, p = 0.03). The infusion was generally well-tolerated apart from in one hyperammonaemic patient, with cirrhosis and possible bleeding unrelated to the infusion, who developed clinical HE that reverted when infusion was discontinued. CONCLUSIONS: Whole-body ammonia clearance and production may be measured separately using the described technique. This technique identified a lower clearance and a higher production of ammonia in patients with cirrhosis, and showed that phenylbutyrate increases clearance, whereas lactulose + rifaximin reduces production. IMPACT AND IMPLICATIONS: High blood ammonia plays a key role in cirrhosis-related brain dysfunction. However, the relative roles of reduced ammonia clearance and increased ammonia production are poorly understood as is the action of ammonia-targeting treatments. This study presents a relatively simple test to measure ammonia metabolism. By using this test, it was possible to show that patients with cirrhosis exhibit decreased ammonia clearance and increased ammonia production compared to healthy persons, and to quantify the unique effects of different ammonia-targeting treatments. The test described herein may be used to examine a range of questions related to normal physiology, pathophysiology and the mechanisms of action of ammonia-targeting treatments. CLINICAL TRIAL NUMBER: ClinicalTrials.gov (1-16-02-297-20).

Experimental non-alcoholic fatty liver disease causes regional liver functional deficits as measured by the capacity for galactose metabolism while whole liver function is preserved.

BACKGROUND: Increasing incidence of non-alcoholic fatty liver disease (NAFLD) calls for improved understanding of how the disease affects metabolic liver function. AIMS: To investigate in vivo effects of different NAFLD stages on metabolic liver function, quantified as regional and total capacity for galactose metabolism in a NAFLD model. METHODS: Male Sprague Dawley rats were fed a high-fat, high-cholesterol diet for 1 or 12 weeks, modelling early or late NAFLD, respectively. Each NAFLD group (n = 8 each) had a control group on standard chow (n = 8 each). Metabolic liver function was assessed by 2-[18F]fluoro-2-deoxy-D-galactose positron emission tomography; regional galactose metabolism was assessed as standardised uptake value (SUV). Liver tissue was harvested for histology and fat quantification. RESULTS: Early NAFLD had median 18% fat by liver volume. Late NAFLD had median 32% fat and varying features of non-alcoholic steatohepatitis (NASH). Median SUV reflecting regional galactose metabolism was reduced in early NAFLD (9.8) and more so in late NAFLD (7.4; p = 0.02), both significantly lower than in controls (12.5). In early NAFLD, lower SUV was quantitatively explained by fat infiltration. In late NAFLD, the SUV decrease was beyond that attributable to fat; probably related to structural NASH features. Total capacity for galactose elimination was intact in both groups, which in late NAFLD was attained by increased fat-free liver mass to 21 g, versus 15 g in early NAFLD and controls (both p ≤ 0.002). CONCLUSION: Regional metabolic liver function was compromised in NAFLD by fat infiltration and structural changes. Still, whole liver metabolic function was preserved in late NAFLD by a marked increase in the fat-free liver mass.

The presence of interferon affects the progression of non-alcoholic fatty liver disease.

Inflammation and metabolic dysfunction are hallmarks of the progression of non-alcoholic fatty liver disease (NAFLD), which is the fastest-growing liver disease worldwide. Emerging evidence indicates that innate immune mechanisms are essential drivers of fibrosis development in chronic inflammatory liver diseases, including NAFLD. In this study, 142 NAFLD patients were genotyped for three IFNL4 single-nucleotide variants in order to investigate the genetic relationship between IFNL4 and fibrosis in NAFLD patients. We observed an overrepresentation of the non-functional IFNL4 allele in patients with significant fibrosis (>F2). Next, we investigated the potential protective role of interferon (IFN) in relation to the development of liver fibrosis in an animal model of non-alcoholic steatohepatitis (NASH). In contradiction to our hypothesis, the results showed an increase in fibrosis in IFN treated animals. Our study clearly indicates that IFN is able to affect the development of liver fibrosis, although our clinical and experimental data are conflicting.

Impaired fibrinolysis without hypercoagulability characterises patients with non-alcoholic fatty liver disease.

INTRODUCTION: Cardiovascular disease is the major cause of mortality in non-alcoholic fatty liver disease (NAFLD), a disease affecting one quarter of the world's population. Coagulation imbalance may be a contributing factor but is yet to be convincingly disclosed. AIM: To perform an extensive mapping of the hemostatic system; primary and secondary hemostasis and the fibrinolytic system in non-diabetic NAFLD patients. MATERIALS AND METHODS: Twenty-five non-diabetic, biopsy-proven NAFLD patients [12 simple steatosis; 13 non-alcoholic steatohepatitis (NASH)] investigated by a comprehensive panel of coagulation and fibrinolysis tests in a cross-sectional study. Fifty age- and sex-matched healthy persons served as controls for each of the dynamic analyses: platelet aggregation, thrombin generation, fibrin formation and lysis. Body composition, insulin resistance makers, and liver fat assessed by proton density magnetic resonance imaging were measured in the patients. RESULTS: Fibrinolytic function was impaired in simple steatosis [median 50% clot lysis time 1123 (min-max, 618-1967) s] and NASH [1448 (521-2618) s] compared to healthy controls [403 (184-1179) s] (p < 0.0001). Plasminogen activator inhibitor-1 (PAI-1) increased stepwise above reference interval from simple steatosis [54 (29-80) ng/ml] to NASH patients [109 (65-153) ng/ml; p = 0.03]. Impaired fibrinolysis correlated with hepatic fat fraction and insulin resistance; PAI-1 correlated with obesity and insulin resistance (ρ ≥ 0.42; p ≤ 0.04). Platelet aggregation, coagulation factors, natural anticoagulants, and thrombin generation were comparable to healthy controls and established reference intervals. CONCLUSIONS: NAFLD patients had impaired fibrinolysis without significant prothrombotic changes in coagulation. The impact of this abnormality on the increased cardiovascular risk remains to be investigated.

Transcatheter Aortic Valve Implantation in Bicuspid Aortic Valve with Aortic Stenosis: a Meta-Analysis and Trial Sequential Analysis

Abstract Objectives: Bicuspid aortic valve (BAV) is an important aetiology of aortic stenosis and the use of transcatheter aortic valve implantation (TAVI) has not been fully explored in this cohort. This systematic review and meta-analysis compared the outcomes of TAVI in stenotic BAV against tricuspid aortic valve (TAV). Methods: An electronic literature search was performed in PubMed, MEDLINE, EMBASE, and Scopus to identify all studies comparing TAVI in stenotic BAV versus TAV. Only studies comparing TAVI in BAV versus TAV were included, without any limit on the study date. Primary endpoints were 30-day and 1-year mortality, while secondary endpoints were postoperative rates of stroke, acute kidney injury (AKI), and permanent pacemaker (PPM) requirement. A trial sequential analysis (TSA) was performed for all endpoints to understand their significance. Results: Thirteen studies met the inclusion criteria (917 BAV and 3079 TAV patients). The BAV cohort was younger (76.8±7.43 years vs. 78.5±7.12 years, P=0.02), had a higher trans-aortic valve gradient (P=0.02), and larger ascending aortic diameters (P<0.0001). No significant difference was shown for primary (30-day mortality [P=0.45] and 1-year mortality [P=0.41]) and secondary endpoints (postoperative stroke [P=0.49], AKI [P=0.14], and PPM requirement [P=0.86]). The BAV group had a higher rate of significant postoperative aortic regurgitation (P=0.002). TSA showed that there was sufficient evidence to conclude the lack of difference in PPM requirements, and 30-day and 1-year mortality between the two cohorts. Conclusion: TAVI gives satisfactory outcomes for treating stenotic BAV and should be considered clinically.

Transcatheter Aortic Valve Implantation in Bicuspid Aortic Valve with Aortic Stenosis: a Meta-Analysis and Trial Sequential Analysis.

OBJECTIVES: Bicuspid aortic valve (BAV) is an important aetiology of aortic stenosis and the use of transcatheter aortic valve implantation (TAVI) has not been fully explored in this cohort. This systematic review and meta-analysis compared the outcomes of TAVI in stenotic BAV against tricuspid aortic valve (TAV). METHODS: An electronic literature search was performed in PubMed, MEDLINE, EMBASE, and Scopus to identify all studies comparing TAVI in stenotic BAV versus TAV. Only studies comparing TAVI in BAV versus TAV were included, without any limit on the study date. Primary endpoints were 30-day and 1-year mortality, while secondary endpoints were postoperative rates of stroke, acute kidney injury (AKI), and permanent pacemaker (PPM) requirement. A trial sequential analysis (TSA) was performed for all endpoints to understand their significance. RESULTS: Thirteen studies met the inclusion criteria (917 BAV and 3079 TAV patients). The BAV cohort was younger (76.8±7.43 years vs. 78.5±7.12 years, P=0.02), had a higher trans-aortic valve gradient (P=0.02), and larger ascending aortic diameters (P<0.0001). No significant difference was shown for primary (30-day mortality [P=0.45] and 1-year mortality [P=0.41]) and secondary endpoints (postoperative stroke [P=0.49], AKI [P=0.14], and PPM requirement [P=0.86]). The BAV group had a higher rate of significant postoperative aortic regurgitation (P=0.002). TSA showed that there was sufficient evidence to conclude the lack of difference in PPM requirements, and 30-day and 1-year mortality between the two cohorts. CONCLUSION: TAVI gives satisfactory outcomes for treating stenotic BAV and should be considered clinically.

Activation and Functional Priming of Blood Neutrophils in Non-Alcoholic Fatty Liver Disease Increases in Non-Alcoholic Steatohepatitis.

INTRODUCTION: In non-alcoholic fatty liver disease (NAFLD), neutrophils in liver infiltrates are activated, which may contribute to disease progression towards non-alcoholic steatohepatitis (NASH). However, the functional status of the blood neutrophils remains unknown and their role in the disease mechanisms is thus uncertain. We therefore characterized activation and function of blood neutrophils in patients with NAFLD in relation to clinical disease markers and the NAFLD plasma milieu. METHODS: We studied 20 patients with NAFLD, among these 6 patients with NASH, and 14 healthy persons. Neutrophil activation, interleukin (IL)-8 production and oxidative burst were measured by flow cytometry on participants´ neutrophils and on healthy neutrophils exposed in vitro to plasma from the study participants. RESULTS: Blood neutrophils from the NASH patients showed a doubling in their expression of the activation marker CD62L. Also, all NAFLD patients had 50-100% increased expression of CD11b. Functionally, NASH neutrophils had 30% elevated IL-8 production and more than doubled spontaneous oxidative burst. In all NAFLD patients, higher spontaneous oxidative burst was associated with worse liver function. Incubation of healthy neutrophils with NAFLD plasma paradoxically slightly reduced CD62L and CD11b expression, and NASH plasma also reduced the frequency of IL-8-producing neutrophils. CONCLUSION: In NAFLD, blood neutrophils are activated, and in NASH also functionally primed. This suggests a progressive neutrophil aggressiveness already present with liver fat infiltration. However, NAFLD plasma in vitro, if anything, had the opposite effect on the healthy neutrophils so the NAFLD-related neutrophil activation cannot be attributed to humoral factors and remains unexplained.

[Hyperammonaemic encephalopathy in adults without liver diseases].

Hyperammonaemic encephalopathy (HAE) in adults in the absence of acute or chronic liver disease is a severe condition caused by inborn errors of metabolism or acquired conditions like bariatric surgery, medications or malignancy as summarised in this review. Metabolic defects are most often caused by partial defects in the urea cycle enzymes demasked by stressors, whereas mechanisms underlying the acquired causes are complex and often multifactorial. Awareness of HAE and knowledge of the causes can help the clinician to deal appropriately with patients presenting with symptoms suggesting HAE and no signs of liver disease.

Cognitive Dysfunction in Non-Alcoholic Fatty Liver Disease-Current Knowledge, Mechanisms and Perspectives.

Non-alcoholic fatty liver disease (NAFLD) has emerged as the hepatic component of the metabolic syndrome and now seemingly affects one-fourth of the world population. Features associated with NAFLD and the metabolic syndrome have frequently been linked to cognitive dysfunction, i.e. systemic inflammation, vascular dysfunction, and sleep apnoea. However, emerging evidence suggests that NAFLD may be a cause of cognitive dysfunction independent of these factors. NAFLD in addition exhibits dysbiosis of the gut microbiota and impaired urea cycle function, favouring systemic ammonia accumulation and further promotes systemic inflammation. Such disruption of the gut-liver-brain axis is essential in the pathogenesis of hepatic encephalopathy, the neuropsychiatric syndrome associated with progressive liver disease. Considering the growing burden of NAFLD, the morbidity from cognitive impairment is expected to have huge societal and economic impact. The present paper provides a review of the available evidence for cognitive dysfunction in NAFLD and outlines its possible mechanisms. Moreover, the clinical challenges of characterizing and diagnosing cognitive dysfunction in NAFLD are discussed.

Glucagon acutely regulates hepatic amino acid catabolism and the effect may be disturbed by steatosis.

OBJECTIVE: Glucagon is well known to regulate blood glucose but may be equally important for amino acid metabolism. Plasma levels of amino acids are regulated by glucagon-dependent mechanism(s), while amino acids stimulate glucagon secretion from alpha cells, completing the recently described liver-alpha cell axis. The mechanisms underlying the cycle and the possible impact of hepatic steatosis are unclear. METHODS: We assessed amino acid clearance in vivo in mice treated with a glucagon receptor antagonist (GRA), transgenic mice with 95% reduction in alpha cells, and mice with hepatic steatosis. In addition, we evaluated urea formation in primary hepatocytes from ob/ob mice and humans, and we studied acute metabolic effects of glucagon in perfused rat livers. We also performed RNA sequencing on livers from glucagon receptor knock-out mice and mice with hepatic steatosis. Finally, we measured individual plasma amino acids and glucagon in healthy controls and in two independent cohorts of patients with biopsy-verified non-alcoholic fatty liver disease (NAFLD). RESULTS: Amino acid clearance was reduced in mice treated with GRA and mice lacking endogenous glucagon (loss of alpha cells) concomitantly with reduced production of urea. Glucagon administration markedly changed the secretion of rat liver metabolites and within minutes increased urea formation in mice, in perfused rat liver, and in primary human hepatocytes. Transcriptomic analyses revealed that three genes responsible for amino acid catabolism (Cps1, Slc7a2, and Slc38a2) were downregulated both in mice with hepatic steatosis and in mice with deletion of the glucagon receptor. Cultured ob/ob hepatocytes produced less urea upon stimulation with mixed amino acids, and amino acid clearance was lower in mice with hepatic steatosis. Glucagon-induced ureagenesis was impaired in perfused rat livers with hepatic steatosis. Patients with NAFLD had hyperglucagonemia and increased levels of glucagonotropic amino acids, including alanine in particular. Both glucagon and alanine levels were reduced after diet-induced reduction in Homeostatic Model Assessment for Insulin Resistance (HOMA-IR, a marker of hepatic steatosis). CONCLUSIONS: Glucagon regulates amino acid metabolism both non-transcriptionally and transcriptionally. Hepatic steatosis may impair glucagon-dependent enhancement of amino acid catabolism.

Low Interleukin-22 Binding Protein Is Associated With High Mortality in Alcoholic Hepatitis and Modulates Interleukin-22 Receptor Expression.

INTRODUCTION: In alcoholic hepatitis (AH), high interleukin (IL)-22 production is associated with disease improvement, purportedly through enhanced infection resistance and liver regeneration. IL-22 binding protein (BP) binds and antagonizes IL-22 bioactivity, but data on IL-22BP in liver disease suggest a complex interplay. Despite the scarcity of human data, IL-22 is in clinical trial as treatment of AH. We, therefore, in patients with AH, described the IL-22 system focusing on IL-22BP and associations with disease course, and mechanistically pursued the human associations in vitro. METHODS: We prospectively studied 41 consecutive patients with AH at diagnosis, days 7 and 90, and followed them for up to 1 year. We measured IL-22 pathway proteins in liver biopsies and blood and investigated IL-22BP effects on IL-22 in hepatocyte cultures. RESULTS: IL-22BP was produced in the gut and was identifiable in the patients with AH' livers. Plasma IL-22BP was only 50% of controls and the IL-22/IL-22BP ratio thus elevated. Consistently, IL-22-inducible genes were upregulated in AH livers at diagnosis. Low plasma IL-22BP was closely associated with high 1-year mortality. In vitro, IL-22 stimulation reduced IL-22 receptor (R) expression, but coincubation with IL-22BP sustained IL-22R expression. In the AH livers, IL-22R mRNA expression was similar to healthy livers, although IL-22R liver protein was higher at diagnosis. DISCUSSION: Plasma IL-22BP was associated with an adverse disease course, possibly because its low level reduces IL-22R expression so that IL-22 bioactivity was reduced. This suggests the IL-BP interplay to be central in AH pathogenesis, and in future treatment trials (see Visual abstract, Supplementary Digital Content 5, http://links.lww.com/CTG/A338).

Human translatability of the GAN diet-induced obese mouse model of non-alcoholic steatohepatitis.

BACKGROUND: Animal models of non-alcoholic steatohepatitis (NASH) are important tools in preclinical research and drug discovery. Gubra-Amylin NASH (GAN) diet-induced obese (DIO) mice represent a model of fibrosing NASH. The present study directly assessed the clinical translatability of the model by head-to-head comparison of liver biopsy histological and transcriptome changes in GAN DIO-NASH mouse and human NASH patients. METHODS: C57Bl/6 J mice were fed chow or the GAN diet rich in saturated fat (40%), fructose (22%) and cholesterol (2%) for ≥38 weeks. Metabolic parameters as well as plasma and liver biomarkers were assessed. Liver biopsy histology and transcriptome signatures were compared to samples from human lean individuals and patients diagnosed with NASH. RESULTS: Liver lesions in GAN DIO-NASH mice showed similar morphological characteristics compared to the NASH patient validation set, including macrosteatosis, lobular inflammation, hepatocyte ballooning degeneration and periportal/perisinusoidal fibrosis. Histomorphometric analysis indicated comparable increases in markers of hepatic lipid accumulation, inflammation and collagen deposition in GAN DIO-NASH mice and NASH patient samples. Liver biopsies from GAN DIO-NASH mice and NASH patients showed comparable dynamics in several gene expression pathways involved in NASH pathogenesis. Consistent with the clinical features of NASH, GAN DIO-NASH mice demonstrated key components of the metabolic syndrome, including obesity and impaired glucose tolerance. CONCLUSIONS: The GAN DIO-NASH mouse model demonstrates good clinical translatability with respect to the histopathological, transcriptional and metabolic aspects of the human disease, highlighting the suitability of the GAN DIO-NASH mouse model for identifying therapeutic targets and characterizing novel drug therapies for NASH.

Early normalization of reduced urea synthesis capacity after direct-acting antiviral therapy in hepatitis C cirrhosis.

Laursen TL, Sandahl TD, Kazankov K, Eriksen PL, Kristensen LH, Holmboe CH, Laursen AL, Vilstrup H, Grønbæk H. Early normalization of reduced urea synthesis capacity after direct-acting antiviral therapy in hepatitis C cirrhosis. Am J Physiol Gastrointest Liver Physiol 319: G151-G156, 2020. First published June 29, 2020; doi:10.1152/ajpgi.00128.2020.-Effects of direct-acting antiviral (DAA) treatment of chronic hepatitis C (CHC) cirrhosis on metabolic liver function are unknown but important for prognosis. Ureagenesis is an essential metabolic liver function involved in whole body nitrogen homeostasis. We aimed to investigate the ureagenesis capacity before and immediately after DAA therapy and relate the findings to hepatic inflammation and structural changes. In an observational before-and-after intervention study, the ureagenesis capacity was quantified by functional hepatic nitrogen clearance (FHNC) in 9 CHC patients with cirrhosis and 10 healthy volunteers. Hepatic inflammation was evaluated by alanine aminotransferase (ALT) and the macrophage activation markers sCD163 and sMR. Structural changes were estimated as liver stiffness and by portal hypertension as the hepatic venous pressure gradient (HVPG). Before treatment, the FHNC in the patients was half of the controls [16.4 L/h (8.2-24.5) vs. 33.4 (29.2-37.6), P = 0.0004]; after successful DAA treatment, it normalized [28.4 (15.9-40.9), P = 0.008 vs. baseline]. DAA treatment normalized ALT (P < 0.0001) and decreased the elevated sCD163 from 5.6 mg/L (3.5-7.7) to 3.4 (2-0-4.8) (P < 0.001) and sMR from 0.35 mg/L (0.21-0.49) to 0.31 (0.17-0.45) (P < 0.01). Liver stiffness fell by 30% (P < 0.05) but remained over the cirrhosis threshold. HVPG was not affected (P = 0.59). DAA treatment restored the severely reduced ureagenesis capacity, along with amelioration of hepatic inflammation but without normalization of other cirrhosis characteristics. Our findings indicate that the anti-inflammatory effect of virus eradication independent of hepatic structural effects rapidly improves metabolic dysfunction. We suggest this effect to be an important early onset part of the expected clinical DAA treatment benefit.NEW & NOTEWORTHY Antiviral treatment of chronic hepatitis C restores the liver's reduced capacity to produce urea along with an improvement in liver inflammation without immediate effects on structural liver changes. The effect is suggested to be an important early onset part of the expected clinical treatment benefit.

Local Versus General Anesthesia in Nonemergency Endovascular Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-Analysis.

The purpose of this systematic review was to assess the perioperative clinical outcomes in using local/regional anesthesia (LA/RA) or general anesthesia (GA) in patients undergoing endovascular abdominal aortic aneurysm repair. A comprehensive electronic literature search was undertaken from inception to September 2018, identifying all randomized and nonrandomized studies comparing LA/RA versus GA in patients with abdominal aortic aneurysm who underwent endovascular repair. A total of 12,024 patients (n = 1,664 LA/RA, n = 10,360 GA) were analyzed from 12 observational studies included in this analysis. No difference in mean age between LA/RA and GA group was noted (73.8 ± 7.8 y v 72.4 ± 7.6 y, 95% confidence interval 0.85 [-0.08 to 1.79]; p = 0.07). No differences in preoperative rate of chronic obstructive pulmonary disease, ischemic heart disease, diabetes mellitus, and American Society of Anesthesiologists grades were noted between the 2 groups (p = 0.21, p = 0.85, p = 0.46, and p = 0.67, respectively). Shorter total surgical time in LA/RA patients was reported (135 ± 40 min v 164 ± 43 min; p < 0.00001). Shorter hospital stay was observed in LA/RA patients (3.6 ± 3.3 d v 4.6 ± 5 d; p = 0.002). No difference in cardiac or renal complications was noted between the LA/RA and GA groups postoperatively (2.7% v 2.5%; p = 0.46 and 1.2% v 1.6%; p = 0.13). Similarly, no difference in vascular complications was noted in LA/RA versus GA patients (8.4% v 7.7%; p = 0.44). Thirty-day morality was not different between the 2 cohorts (2% v 1.7%; p = 0.97). Use of LA/RA in selective endovascular abdominal aortic aneurysm repair procedures provides satisfactory and comparable perioperative outcomes with those of GA, with the advantage of a shorter hospital stay. A large randomized controlled trial or multicenter study is required to confirm the present study's findings.

The Future of Open Heart Surgery in the Era of Robotic and Minimal Surgical Interventions.

It has been over two decades since the very first robotic cardiac surgery was performed. Over the years, there has been an increase in the demand for less invasive cardiac surgical techniques. Developments in technology and engineering have provided an opportunity for robotic surgery to be applied to a variety of cardiac procedures, including coronary revascularisation, mitral valve surgery, atrial fibrillation ablation, and others. In coronary revascularisation, it is becoming more widely used in single vessel, as well as hybrid coronary artery approaches. Currently, several international centres are specialising in a totally endoscopic coronary artery bypass surgery involving multiple vessels. Mitral valve and other intracardiac pathologies such as atrial septal defect and intracardiac tumour are also increasingly being addressed robotically. Even though some studies have shown good results with robot-assisted cardiac surgery, there are still concerns about safety, cost and clinical efficacy. There are also limitations and additional challenges with the management of cardiopulmonary bypass and myocardial protection during robotic surgery. Implementing novel strategies to manage these challenges, together with careful patient selection can go a long way to producing satisfactory results. This review examines the current evidence behind robotic surgery in various aspects of cardiac surgery.